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 *   Copyright (c) 2022 Huawei Device Co., Ltd.
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import Big5DistributionAnalysis from './distributionanalysis/Big5DistributionAnalysis';
import Big5SMModel              from './statemachine/Big5SMModel';
import CharsetProber            from './CharsetProber';
import CodingStateMachine       from './statemachine/CodingStateMachine';
import Constants                from '../Constants';
import {ProbingState}           from './CharsetProber';
import SMModel                  from './statemachine/SMModel';

class Big5Prober extends CharsetProber {
  ////////////////////////////////////////////////////////////////
  // fields
  ////////////////////////////////////////////////////////////////
  private codingSM:CodingStateMachine;
  private state:ProbingState;
  private distributionAnalyzer:Big5DistributionAnalysis;
  private lastChar:ArrayBuffer;
  private static smModel:SMModel = new Big5SMModel();

  ////////////////////////////////////////////////////////////////
  // methods
  ////////////////////////////////////////////////////////////////
  public constructor() {
    super();
    this.codingSM = new CodingStateMachine(Big5Prober.smModel);
    this.distributionAnalyzer = new Big5DistributionAnalysis();
    this.lastChar = new ArrayBuffer(2);
    this.reset();
  }

  public getCharSetName():string {
    return Constants.CHARSET_BIG5;
  }

  public getConfidence():number {
    return this.distributionAnalyzer.getConfidence();
  }

  public getState():ProbingState {
    return this.state;
  }

  public handleData(buf:ArrayBuffer, offset:number, length:number):ProbingState {
    let codingState:number;
    let maxPos:number = offset + length;
    let tempIntArray = new Int8Array(buf);
    for (let i:number=offset; i<maxPos; ++i) {
      codingState = this.codingSM.nextState(tempIntArray[i]);
      if (codingState == SMModel.ERROR) {
        this.state = ProbingState.NOT_ME;
        break;
      }
      if (codingState == SMModel.ITSME) {
         this.state = ProbingState.FOUND_IT;
         break;
      }
      if (codingState == SMModel.START) {
        let charLen:number = this.codingSM.getCurrentCharLen();
        if (i == offset) {
          this.lastChar[1] = tempIntArray[offset];
          this.distributionAnalyzer.handleOneChar(this.lastChar, 0, charLen);
        } else {
          this.distributionAnalyzer.handleOneChar(buf, i-1, charLen);
        }
      }
    }

    this.lastChar[0] = tempIntArray[maxPos-1];
    if (this.state == ProbingState.DETECTING) {
      if (this.distributionAnalyzer.gotEnoughData() && this.getConfidence() > CharsetProber.SHORTCUT_THRESHOLD) {
        this.state = ProbingState.FOUND_IT;
      }
    }

    return this.state;
  }

  public reset():void {
    this.codingSM.reset();
    this.state = ProbingState.DETECTING;
    this.distributionAnalyzer.reset();
    let temp = new Int8Array(this.lastChar);
    this.lastChar = temp.fill(0);
  }

  public setOption() {
  }
}

export default Big5Prober;